Parallel filter distortions...thing.

[patrick398]

Just been fiddling around on the breadboard with a buffer splitting guitar signal into a low pass filter into an IC based distortion, and into a High pass filter into a transistor distortion/fuzz then summing the two.

Not sure if that's jibberish. So:

Guitar:------>Buffer----->LPF--->IC distortion------>
                              |                                                    Summed at unused op-amp.
                              - -->HPF---> Transistor dirt------>


I just wanted to see what it would sound like. It was surprisingly good. I'm trying to get quite a tight, well defined bottom end distortion, and i'm not totally sure what i want out of the high end yet but i'm encouraged by the results so far.

Anyway, there's no way this hasn't been done before so just wondering if anyone can point me in the direction of a schematic that does something similar. I'd be interesting in studying it.

Alternatively give me all the reasons it's a bad idea or ways to do it way easier.
There's no way i've had a good idea off my own back.

Cheers

[GibsonGM]

Anderton did a very similar (and more complex!) thing here:

https://www.paia.com/ProdArticles/quadrafz-design.htm

[patrick398]

Anderton did a very similar (and more complex!) thing here:

Jeez! You're not wrong. Might take me a while to get my head round that one.
You just trying to shut me up?   

[Rob Strand]

Jeez! You're not wrong. Might take me a while to get my head round that one.
You just trying to shut me up?

I don't think that one has the low-end bleed like yours.  From what I can see bypass is clean and effect is effect.

You adjust the level of different bands before they go to the fuzz.  The fuzz is connected externally in the fx loop.  Sort of a pre-distortion graphic EQ.

There's one extra quirk in that if you don't plug in a fuzz the effects loop then the effects mode inserts a adjustable cut-off low-pass filter in place of the fuzz.

[Mark Hammer]

https://www.diystompboxes.com/smfforum/index.php?topic=51810.0

[GibsonGM]

I remember that one, Mark! I have to BB that some time soon, looks interesting!

Patrick, I have a feeling the Quadra and Mark's Flexi will do anything BUT shut you up, LOL!! 

[patrick398]

Patrick, I have a feeling the Quadra and Mark's Flexi will do anything BUT shut you up, LOL!! 

I have several sheets of paper entitled 'Badly phrased questions for Mike' 

https://www.diystompboxes.com/smfforum/index.php?topic=51810.0

Thanks Mark that looks very interesting indeed. The longer i look at that Drive Balance control the less i understand it.
I like the idea of using different sources of distortion for the HPF and LPF which is why i went for the IC and Transistor set up. I need to strip it all off the BB and start again. What i had when i first started sounded fantastic, it's gotten steadily worse.

[patrick398]

Also, am i right in thinking that the corner frequency for both your HPF and LPF is set at around 900Hz? Is it wise to keep them equal?

[Mark Hammer]

Thanks Mark that looks very interesting indeed. The longer i look at that Drive Balance control the less i understand it.
I like the idea of using different sources of distortion for the HPF and LPF which is why i went for the IC and Transistor set up. I need to strip it all off the BB and start again. What i had when i first started sounded fantastic, it's gotten steadily worse.

The two paths are non-inverting op-amps.  Since the gain of each is set by a resistance to ground from the non-inverting pin, I figured I could use a single pot for reciprocal control of gain, by tying the wiper to ground.  That way, as you increase the gain on the one "side", you decrease it on the other.  That would let me use three pots to adjust the drive, balance between paths, and overall output level.  In retrospect, as elegant as the reciprocal drive idea was, you couldn't necessarily make the thing do all possible tricks.  So I would suggest using separate gain pots for each path/section.

[blackieNYC]

Mark, I've been looking at your Flexidrive. But with individual controls.  Any reason the top end couldn't have clippers to ground instead of in the loop?

[Mark Hammer]

Hi Alan.
I just figured that the upper band could benefit from being a little more compressed, while the lower band could afford to be more "ragged".  But feel free to try other approaches.

[temol]

Maybe not exactly the same setup you describe but this one also has two separate gain stages. Schematic

T.

[sixthfloor]

The VFE Triumvirate circuit might be of interest. Lows, mids and highs have their independant distortions and volumes before being blended together.

http://vfepedals.com/schematics/triumvirate.pdf

[patrick398]

Thanks for all the replies, lots of interesting stuff suggested. The triumpvirate looks cool. Still using only ICs but with different clipping methods looks interesting, especially mosfet for low end clipping. Might give that one a try.
I'll try and update as i go.
When i finish tinkering with the circuit i might make it my first PCB etch just to bring in the new year with a whole new world of pain and frustration. Begin as you mean to continue and all that

[marcelomd]

VFE's DragonHound is also worth checking.

[Ben N]

A CMOS chip might be an interesting distortion engine for a multiband distortion.

[patrick398]

VFE's DragonHound is also worth checking.

Great, thanks for that. Anybody care to explain how this is doing the filtering. I think i'm being stupid.
I thought C1, R3 and R2, C5 would provide the filters but the numbers just don't add up.

[faevry]

I've worked on something quite close:

- A sort of crossover filter using a amz active splitter 1 in 3 out with added filter on each : a HP, a LP and BP.
- A switchable CMOS (4049) Drive and a CMOS Fuzz on each HP and BP (schematics from Tim Escobedo)
- A half clean boost on LP (4049, from Tim too i think)
- Active blender at the end

It was more like a newbie block-building game as you can see, but... after hours of work on the proto, I was quite disapointed by result.

What I learned from it :
- Before I add the active buffered mixer, it sounded like garbage.
- The stompbox was ridiculously big and with too many options
- Level matching between each drive / fuzz is really important
- Each Fuzz and Drive must have caricatural differences
- The ratio Size / Awsomeness was terrible...
- CMOS are awsome !

Also, I've been able to use a Chaise Bliss Brother and a Empress Multidrive, that was not as extreme as mine but sound close (and better)

[marcelomd]

VFE's DragonHound is also worth checking.

Great, thanks for that. Anybody care to explain how this is doing the filtering. I think i'm being stupid.
I thought C1, R3 and R2, C5 would provide the filters but the numbers just don't add up.

Sorry for the delay.
This effect is just 2 full range distortions in parallel with a panner at the end. Not exactly what you are doing, but I meant more for generating ideas. The idea of the DragonHound is to blend between flavors of overdrive. The Fender Pugilist works more or less the same.
R1, C1, and R2, C2, are just decoupling and limiting input. R3, R4 and R5 are bias resistors. C5 is there to cut some highs, probably RF.

The problem with multiband distortion, for me, besides level matching, is that it is not enough to filter the input. Overdrive/distortion/fuzz type effects create components with high frequencies. The bottom, mid and high end are creating high frequency content, so it may become overwhelming. It is just too much going on for me.

A single (semi)clean channel plus effect seems to be the sweet spot (for me).

Klon Centaur is a tri band effect, but as you increase overdrive in the mids, it lowers the high frequency volume. Clean bass is always present.

[rankot]

My guitarist and I discussed similar topic few months ago and decide to try building it after New Year, however, there are a lots of great ideas here to study!